Alluvial-transported soil, Biology

Assignment Help:

Alluvial

Materials of this catego~ya re deposited by running water in the form offroodplains, river terraces, deltas and alluvial fans. These deposits have two outstanding characteristics by, which they can usually be recognised with ease. Fit, the individual particles tend to be rounded and smootlfed by the action of running water. Second, the layers are usually distinct in that each contain particles of a particular range or size class depending upon the speed of the transporting water. Coarse materials are laid by swift water currents, whereas, fine particles are deposited by relatively calm waters.

Alluvial soils are found bo~deringri vers and slow moving bodies of water. When first formed; these deposits are sa low that they are frequently flooded at high-water stages, and at such times they receive additional increments of fine sediment, especially if they are well vegetated. At this stage of development, they are called flood plains. As the stream cuts its channel deeper, the flood plain is left above the reach of high water and is called a terrace. Large streams are frequently bordered by a series of terraces, the oldest being at considerable heights above the present water level.

Where streams enter a lake or a sea, the deposit of silt and clay that settles down at the edge of the still water may build a delta which gradually lengthens until it extends beyond the mouth of the stream. The Sunderbans in West Bengal and Bangladesh are examples of deltas, which supprt mangrove type of vegetation. Alluvial fans are formed where a stream descends from uplands, and a sudden change in gradient may sometimes occur as the stream emerges at the lower level. Deposition of sediments is thereby forced, giving rise to alluvial fans. They differ from a delta in their location and in the character of their debris. Fan material is often gravel and stony in nature
and is well drained.

Among the transported soils, the alluvial soils of the Indoagetic Plains are highly productive and have been under'cultivation for several thousands of years. The parent material of the Indo-Gangetic alluvial soils is actually in the Himalayas. Mountain and hill washes contribute huge quaiitities of sediments brought down by the rivers and deposited in the plains below. Most of the alluvial soils are under intensive crop cultivation.


Related Discussions:- Alluvial-transported soil

Control of the cell cycle, The cell cycle is controlled by a cyclically ope...

The cell cycle is controlled by a cyclically operating set of reaction sequences that both trigger and coordinate key events in the cell cycle • The cell-cycle control system is

Excretory system - kidney, Kidney - 2 in number. Dark red. Sl...

Kidney - 2 in number. Dark red. Slightly flattened. Bean shaped. 10 cm. long, 5 cm wide and 4 cm thick (In rabbit 20-25 mm). Weighing 150 gm in male 135 gm in fema

Explain synaptic transmission between neurons, Q. How does synaptic transmi...

Q. How does synaptic transmission between neurons take place? The propagation of the action potential along the axon reaches the region immediately anterior to the presynaptic

Explain nutrient and storage proteins, Nutrient and Storage proteins Th...

Nutrient and Storage proteins These proteins store amino acids. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo. Casein, the prote

Describe technique operation prosthetic valve endocarditis, Describe the Te...

Describe the Technique of Operation in prosthetic valve endocarditis? The operative principle is drainage of abscess, removal of debris and valve rep or replacement to reverse

Chordata.., write the classification of chordata?

write the classification of chordata?

Oreopithecus, Oreopithecus, a late rniocene primate had very close resembla...

Oreopithecus, a late rniocene primate had very close resemblances to those of gibbons, although the tooth structure showed that the animal was only a monkey and not a hominoid. Ano

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd